The Prom Effect?

Researchers have long puzzled over the relatively poor health and education outcomes for babies born in the winter months. Past explanations have focused on school attendance laws, vitamin D exposure, and other environmental factors, but economists Kasey Buckles and Daniel Hungerman have found an overlooked explanation. They argue that less-educated women seem to have their children in winter, a fact that may explain some of the phenomenon. Our own Daniel Hamermesh says of the paper: “It means you have to think about things more than you want to think.” Buckles and Hungerman aren’t exactly sure why socioeconomic background drives the season of conception, but they offer the “prom” effect as one possible explanation: “January is, after all, about nine months after many of these soirées.” [%comments]

COMMENTS: 40

The one minor flaw in this theory is that most lower socio-economic kids don’t go to the prom. That’s a rite usually reserved to those that can afford the dress and tux. Most of them hang out somewhere at a party. But, I think the outcome would be the same.

However, before birth must come conception. Evolutionarily, there may be an advantage to being reproductively “ready” at all times yet that advantage would be tempered by the seasonal fluctuation in offspring survival.

The propensity for lower income women to have more babies in the winter months may be a result of seasonal changes stimulating hormonal shifts in men and women as the days lengthen. Or, poorer workers have a couple weeks of vacation that they take in the summer…..

First, are you calling Jesus, the ultimate winter baby, an underachiever?

If someone is going to the prom, that would tend to imply high school graduation, right? That’s kind of a milestone in education. Should that be considered “less educated”?

Further, are these “winter babies” the offspring of recent high school graduates? If they are instead the offspring of, say, 20somethings, then it’s not the “prom effect,” right?

Maybe the March/April/May conceptions are due to people figuring out that they have an income tax refund coming, celebrating wildly and without protection (after all, they may figure they can afford a baby).

Or, since the conception months are some of the nicest months of the year, maybe folks are just experiencing “spring fever” and–viola! (These months also happen to coincide with Spring Break–where otherwise smart girls and boys get drop-dead stupid for a week.) More educated people don’t experience this because they are too busy at their Goldman Sachs jobs to pay any attention to the weather (except how it affect commodity prices) and to notice the curves of the female fauna.

Of course, the REAL REASON is…St. Patrick’s Day hook-ups. Drunken revelry appears to be an almost surefire way to conceive.

The point of the paper really isn’t to argue for a “prom effect” but to note that quarter of birth or season of birth is non-random and likely correlated with unobservable factors that ultimately influence labor market outcomes. It’s helpful to mention that there was a famous paper by Josh Angrist and Alan Krueger in the early 1990s that used quarter of birth as an instrument for schooling attainment, which given state mandatory schooling laws, would have resulted in some students receiving randomly more schooling since they would hit the relevant age cutoff sooner than others. That paper, and the many others like it, all argue that season of birth is basically random. This paper’s main value is to call that assumption into question.